Cad drawing problem

[peige]

Trying to do a blend between three features, this one has me stumped.

Rad 1 to Rad 2 going through point 3. I don't know the rad but one blending rad should hit all three features (ie tangential blends to 1&2 but through 3). Does anyone know how to construct the geometry that will be the centre of the arc that scribes through all three?

The full circle gives you an idea of the type of bend I need, the green lines are the profile I have so far.

I know, quite random for GD but I know a few CAD people read here.


blend

 

[peige]

Actually its more like this in that its both rads and touching the line. I don't think its geometrically possible to do the first one.

blend2

3 point arc doesn't work, it doesn't like two of the points actually being arcs

I think this link will work to a dxf of the file.

https://drive.google.com/file/d/0BwpzSqjCqwdxa2dOb1RmcW9rZWM/view?usp=sharing

 

[peige]

Hmm pretty sure 3 point would work using the tangent snap on most of the software I use

Maybe try another drawing package?

I've just got oneCNC, its primarily a drawing to CNC code package but this is the first thing i've tried to draw that I can't

 

[peige]

Well by trying over and over I have arrived at a 17.2 rad which is pretty much close enough.

Still like to know how to do it properly!

/edit. Ok got the above, even smaller than my 17.2 that seemed near... 15.87 it is!

Thanks

 

[peige]

nevermind just seen your post

edit2: even took the wrong point, doh.

i'm probably just stupid but what do you actually need?
the 1st picture is pretty much impossible to get a proper match based of the circle. see pic I just a used a 3point arc (red line), showing the issue

Thanks for trying though, it was a hard one to explain. The answer of 15.878 is very different to the customers drawn 18.48 which explains why it wouldn't work

 

[peige]